TYPO3 Core

Corrected the example and added code highlighting

Actually it should be

Time for doing strpos for each element in original loop

Time for flipping exploded list ONCE + doing isset on the generated array for each element in the original loop

Here's a benchmark: http://ryanday.org/index_php.php

The more items to check and/or the longer the list, the stronger the impact.
The memory consumption should be slightly increased though, due to the newly introduced temporary array.
On the other hand we will get back that memory, since we won't call inList anymore.

All tests run using php version 5.2.4

hmmm

Here's the modified code for testing on different systems using the same "inList" method as the core currently does.
I moved the array_flip into the measuring parts to get correct results including the flipping step.

function inList($list, $item) {
    return strpos(',' . $list . ',', ',' . $item . ',') !== FALSE;
}

$letters = 'a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,u,r,s,t,u,v,w,x,y,z';
$letter_array = explode(',', $letters);
$t1 = microtime(true);
for($i=0;$i<=10000;$i++){
    foreach($letter_array as $l){
        if(inList($letters,$l)!==false){

        }
    }
}
$ms1 = (microtime(true)-$t1)*1000;
$t2 = microtime(true);
for($i=0;$i<=10000;$i++){
    foreach($letter_array as $l){
        if(in_array($l,$letter_array)){

        }
    }
}

$ms2 = (microtime(true)-$t2)*1000;
$t3 = microtime(true);
for($i=0;$i<=10000;$i++){
$letter_assoc = array_flip($letter_array);
    foreach($letter_array as $l){
        if(isset($letter_assoc[$l])){

        }
    }
}
$ms3 = (microtime(true)-$t3)*1000;
$t4 = microtime(true);
for($i=0;$i<=10000;$i++){
$letter_assoc = array_flip($letter_array);
    foreach($letter_array as $l){
        if(array_key_exists($l,$letter_assoc)){

        }
    }
}
$ms4 = (microtime(true)-$t4)*1000;
echo "strpos: $ms1
";
echo "in_array: $ms2
";
echo "isset: $ms3
";
echo "array_key_exists: $ms4
";

Results with PHP 5.4 using PHP tester website:

strpos:          318.2098865509
in_array:        250.89502334595
isset:            52.170991897583
array_key_exists: 89.164018630981

Results with PHP 5.5 using onlinephpfunctions website:

strpos:           228.17492485046
in_array:         197.90005683899
isset:             33.337831497192
array_key_exists:  48.688173294067

These results are just single results, but the difference is big enough to assume, that array_flip + isset will usually win compared to inList.

Patch set 2 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at http://review.typo3.org/37136

These benchmarks are insufficient IMHO.

We need to know numbers for PHP 5.5 and 5.6. For a fair comparison this needs to compare a inList() call with the full set of calls to trimExplode()+flip+isset.
I really doubt that a simple strpos() can be beat by array magic.

Patch set 1 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at http://review.typo3.org/37137

Patch set 1 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at http://review.typo3.org/37138

Patch set 2 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at http://review.typo3.org/37138

Patch set 1 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at http://review.typo3.org/37139

Patch set 3 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at http://review.typo3.org/37136

Patch set 4 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at http://review.typo3.org/37136

Patch set 1 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at http://review.typo3.org/37339

Please do not add several patches for one issue. Please create further issues for other patches an related the issues to each other. I was not aware there are several patches resolving the same issue!

If I remember correctly in the end there were two (and others abandoned), since both targeted other sysexts. In the end imho it wasn't that big so it could have gone into one review - but maybe that was not really obvious in the original review or so which got split up then.

The original stuff back then was aimed to be one single patch with lots of changes.
Now the advice was: Although this is actually one task, please split it up into smaller patches, so people can easily review them and decide per patch, if this should make it into the core or not.
Nobody asked for separate issues as well, which is why each patch has been connected to this "umbrella issue".

Patch set 2 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at http://review.typo3.org/37139

Patch set 3 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at http://review.typo3.org/37139

Patch set 4 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at http://review.typo3.org/37139

Patch set 5 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/37139

Patch set 6 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/37139